Is it possible to disable recently added Introduce Yourself feature?
Which feature do you mean? The trust level 0 to 1 PM? You can edit the copy for it in admin, customize.
It’s available in /admin/customize/site_texts/system_messages.welcome_tl1_user.text_body_template.
Here we can edit message body but I want to disable it.
I believe you’ll need to turn off the send tl1 welcome message site setting to disable this feature.
That copy is kinda broken and from a rather old version, so I’d also update to latest.